So, you've found the best source of RE info on the planet.....AND allegedly you can find sellers.... but you're quitting. 

1. Tenant signed a 1 year lease, with a Move-In form with pictures; and the pictures showed the house with no insects. 2. A few days later, the tenant says there's trash and mice droppings in the kitchen cabinets. 3. ...

In that letter the lawyer relented and said that the tenant would be responsible for March rent (did not give any notice) but reserved the right to challenge the retention of the security department arising from alleged repairs and fees.I responded back attacking this letter in multiple ways:1: There are different levels of disability and I needed her to provide proof that she is truly “totally disabled” as defined in the statute.2: The general statute calls for allowing the tenant to leave, “without the penalty or liability for the remaining term of the lease” and we had re-rented it and not made her responsible for additional liability but did make her responsible for the cost to re-rent the property which is clearly called out in the lease and is true payments that have to be made by the owner due to the tenant violating the lease agreement.

Google also says she allegedly tried to run an adoption scam.2) Female in her 30s with drug charges within the past few years. 3) Guy with tons of charge-offs in small claims court.This is a roommate setting.

I get the impression you think he should "help you out" just because he's your brother and allegedly doing well for himself.

Now we are being asked for our best and highest due to alleged multiple offers.What say this room of great minds?

Whether or not the tenant is an alleged criminal is a mute point. 

But, as the NYT reports, several US states are now working to ban them entirely, alleging they mislead consumers.So, how do they work?

I don’t think either are dead, but I have heard some chirpings about Vacasa, and they allegedly advertise on a the pertinent vacation rental websites. 

You have no way to respond to that "alleged neighbor".